The tariffs for solar power could increase between 25-45 paise per unit (kWh) due to Basic Customs Duty (BCD) on imported solar cells and modules, according to a rating agency. The Ministry of New and Renewable Energy's (MNRE) announcement of the BCD implementation on imported solar cells (25 per cent) and modules (40 per cent) starting April 1 could increase the solar power tariff, it said.